DIY DC Motor with Optical Encoder

[sato4kaiba]

Resolution of the encoder is not high enough for the motor's slow rotation. Also the PWM freq needs to be 3* the sample rate for the encoder. The sampling for the encoder needs to be selected for the encoder design. Encoder sample rate should be at least 2*Nyquist

[ivanblogs]

@sato4kaiba This is simply the encoder hooked to a motor and an adjustable linear power supply. There is no PWM, sampling or feedback. Once it was hooked to a servo-controller it provided rock-solid movement.

[tom40K]

I imagine it's the motor itself cogging, since your initially running it at such slow speeds. Figure it's happening when the armature brushes are bridging the adjacent commutator bars, torque pulses when your putting power through two coils instead of one.  Once it gets going faster, inertia smooths it out.

[CharlieMoher]

Can you tell me what encoder you are using and does the wheel come with it ?

[ivanblogs]

US Digital E4P encoder (~US$20)

search:"E4P OEM Miniature Optical Kit Encoder"

[thouston314159]

Pick yourself up a Kollmorgen Servodisc motor and you won't have any more cogging.

[ivanblogs]

If I can get them new for $67 (like the current motor), Unfortunately, they seem hideously expensive.

[ravingking]

im trying to use the same principles to make a scratch wheel for djing. wish i dad your tools

[gorgeousmale]

can u plz tell me how optical encoder works along with the motor

[ivanblogs]

The optical encoder is used to sense the position of the motor.

This can be used by a motor controller to rotate the motor to a particlar position.

This can be seen in action in my video "DIY Servo Controller - Four Channel"

[CharlieMoher]

Get a copy of "Building Robot Drive Trains" by Clark and Owings. Fantastic book on this and more. Maybe in your library.